Tuesday, October 12, 2010

New Theories Test Our Understanding of Nature’s Most Elemental Force | Popular Science: Astrophysicists Maximo Bañados and Pedro Ferreira of the University of Oxford replaced the Einstein-Hilbert action—the equation from which all of general relativity’s other equations are derived—with a modified Born-Infeld action, which describes electromagnetism. With Born-Infeld conditions in place, Ferreira and Bañados were able to replicate Einsteinian gravity in normal situations, and they were also consistent with the conditions scientists have observed about the origins of the universe.

According to Ferreira and Bañados, gravity is not strong enough to crumple the universe’s mass into an infinitely dense point, but with the limit they placed on gravity, it could have compressed the universe into an extremely small ball.

Rather than emerging from a point, that ball may have been the densest part of an ongoing process, in which a previous universe had collapsed in on itself, “bounced” against the limits of density, and then expanded again to become our current universe. Or, after its initial growth, the universe may have paused before expanding as it does today. Future analysis of gravitational waves left over from the early universe could validate the work, Ferreira says.